Flotation of sulfide ores

ABSTRACT

An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity of a flotation collector comprising a compound corresponding to the formula WHEREIN R and R2 are hydrocarbon groups and R1 is an alkylene group. Certain of the indicated compounds provide enhanced recovery of and/or selectivity of sulfide minerals of Cu, Zn, Mo, Co, Ni, Pb and As over iron sulfide.

United States Patent David J. Collins Walnut Creek;

Guy H. Harris, Concord, both of, Calif. [21] Appl. No. 796,158

[72] Inventors [22] Filed Feb. 3, 1969 [45] Patented July 6, 1971 [73] Assignee The Dow Chemical Company Midland, Mich.

[54] FLOTATION OF SULFIDE ORES 6 Claims, No Drawings [52] 1.1.8. Cl 209/166, 260/455 [51] 1nt.C1 803d 1/02, C07c 153/07 [50] Field 01' Search 209/166,

3,290,351 12/1966 McKay 260/455 2.835.625 5/1958 Lo 260/455 X FOREIGN PATENTS 750,568 6/1956 Great Britain.... 260/455 1,179,312 12/1958 France 260/455 Primary Examiner- Frank W. Lutter Assistant Examiner-Robert Halper Attorneys-Griswold and Burdick, Bruce M. Kanuch and William R. Norris ABSTRACT: An improvement in the concentration of ores by flotation which comprises subjecting a sulfide ore in the form of a pulp to a flotation process in the presence of an effective quantity of a flotation collector comprising a compound corresponding to the formula wherein R and R are hydrocarbon groups and R, is an alkylene group. Certain of the indicated compounds provide enhanced recovery of and/or selectivity of sulfide minerals of Cu, Zn, Mo, Co, Ni, Pb and As over iron sulfide.

FLOTATION OF SULFIDE ORES BACKGROUND Flotation is a process of treating a mixture of finely divided mineral solids, e.g.. a pulverulent ore, suspended in a liquid whereby a portion of such solids are separated from other finely divided mineral solids by introducing a gas (or providing a gas in situ) into the liquid to produce a frothy mass containing certain desired solids on the top of the liquid, and leaving suspended (unfrothed) solids in the liquid.

Flotation is based on the principle that introducing a gas into a liquid containing solid particles of difierent materials suspended therein causes adherence of some gas to certain suspended solids and not to others and makes the particles having the gas thus adhered thereto lighter than the liquid. Accordingly, they rise to the top of the liquid to form a froth.

Various flotation agents have been admixed with the suspension to improve the frothing process. Such added agents are classed according to the function to be performed: collectors, e.g., high carbon chain compounds such as collectors for sulfide minerals including xanthates, thionocarbamates, and the like; frothers which impart the property of forming a stable froth, e.g., natural oils such as pine oil and eucalyptus oil; modifiers such as activators to induce flotation in the presence of a collector, e.g., copper sulfate; depressants, e.g., sodium cyanide, which tend to prevent a collector from functioning as such on a mineral which it is desired to retain in the liquid, and thereby discourage a substance from being carried up and forming a part of the froth; pH regulators to produce optimum metallurgical results, e.g., lime, soda ash and the like.

it is of importance to bear in mind that additaments of the above type are selected for use according to the nature of the ore, the mineral sought to be recovered, and the other additaments which are to be used in combination therewith.

An understanding of the phenomena which makes flotation a particularly valuable industrial operation is not essential to the practice of the present invention. They appear, however, to be largely associated with selective afi'mity of the surface of particulated solids, suspended in a liquid containing entrapped gas, for the liquid on one hand, the gas on the other.

The flotation principle is applied in a number of mineral separation processes among which is the selective separation of such minerals as sulfide copper minerals, sulfide zinc minerals, sulfide molybdenum minerals and others from sulfide iron minerals. The present invention concerns the use ofa unique class of compounds as collection agents in a flotation process. With some of these collectors better recoveries are realized and with others improved selectivity is achieved. Certain of these agents produce improvement in both aspects.

SUMMARY The present invention concerns an improved method of flotation separation of sulfide minerals which comprises subjecting a sulfide ore to a flotation process in the presence of a compound corresponding to the formula wherein R is a hydrocarbyl group, other than an aryl or alkaryl; R is an alkylene group, and R, is a hydrocarbyl group other than aryl or alkaryl; said compounds acting as flotation collectors in the concentration of sulfide minerals of copper, zinc, molybdenum, cobalt, nickel, lead, arsenic and others from ores in preference to other minerals.

PREFERRED EMBODIMENTS In the practice of the present invention the present compounds are employed as flotation collectors using standard flotation techniques. Preferable compounds correspond to the formula Q H 3 wherein R represents a hydrocarbyl group selected from the group consisting of a branched or straight chain alkyl or alkenyl group or an cycloalkyl or cycloalkenyl group, preferably containing from 1 to 10 carbon atoms, or an aralkyl group; R, represents an alkylene group, preferably containing from 1 to 6 carbon atoms, and R represents a hydrocarbyl group selected from the group consisting of an alkyl, alkenyl, cycloalkyl or cycloalkenyl group, preferably containing from 1 to 8 carbon atoms, an aralkyl or aralkenyl group.

The flotation collector compounds as defined herein can be prepared by the interaction of an ester of a primary amino acid with a compound corresponding to the general formula wherein M represents a metal cation and R, is the same as defined hereinbefore, the desired product being obtained with coformation of the metal acetate through cleavage of the bond.

The flotation collector compounds as defined herein are particularly suitable for use in standard flotation processes to concentrate copper sulfide and other like minerals from sulfide ores. In such processes, a pulp is first prepared by wet grinding the ore to a suitable size with or without a pH modifier. A suitable frothing agent is then added, e.g., pine oil, cresylic acid, polyalkoxyparaffin and the like. An effective quantity of the flotation collector compound as defined herein is then added usually ranging from about 0.01 lb. to about 0.25 lb. per ton of pulp and the pulp usually agitated and.

areated. The copper sulfide minerals and other like sulfide minerals, except iron sulfide, collect as a froth which is readily overflowed or skimmed off from the residual gangue and other nondesired materials and the metal values therein recovered.

The following Examples will facilitate a more complete understanding of the present invention but they are not meant to limit the scope of the invention to the specific embodiments incorporated therein.

EXAMPLE 1 Various species of flotation collector compounds within the scope of the present invention were employed in the flotation recovery of copper from a sulfide ore obtained from Southwestern United States employing the following procedure. A sample of ore was ground for 4 minutes at a pulp density of 645 percent by weight solids with 2.0 lbs/ton of lime. The pulp was then conditioned for 2 minutes at a pH of 10.3 with a collector compound and 0.05 lbs/ton of a frother. The pulp was then floated for 4 minutes. A standard flotation collector compound consisting of a thionocarbamate compound corresponding to the formula was employed as a control. The specific collector compounds, concentrations of collectors, and analysis of the concentrates and tailings for copper are set forth in the following Table I.

'1 .u; LE l Run Lb./ton Cu in Percent Cu Number (ollcctor compound added tails recovered (ontroL ('ontrul H, 01 .389 51. 8

o n r! l C:lI50C-Cli2.\'*'O-Cli(ClI3); 0.01 0. 272 55.0

free amine was then added to an aqueous solution containing a EXAMPLE 2 compound corresponding to the formula Other compounds, within the scope of the present invention, were employed as flotation collectors in a flotation process to separate copper from a different copper sulfide ore obtained from the Southwestern United States.

A sample of the ore was wet ground for 3 minutes at a pulp density of 62.5 percent by weight solids with 0.8 lb./ton of lime to provide a concentrate. The pulp was then conditioned with the quantity of a collector compound as shown in Table ll and 0.l3 lb./ton of a frother. The pulp was then floated for 5 minutes. A standard flotation collector compound consisting of a thionocarbamate compound corresponding to the formula was employed as a control. The specific collector compounds, quantities of addition, and results obtained are set forth in Table ll.

the corresponding butyl ester of the substituted glycine was TABLE II Concentrate Tail assay, assay, Percent percent percent recoveries LbJton Run No. Collector compound added Cu Fe Cu Fe Cu Fe 1 Control ,.032 12.4 17.9 .081 1.22 85.8 36.8

r e r 2 CzH OC-CHzCH-NCOC:H .032 14.4 17.6 .080 1.48 86.0 28.8

it r r 3 CzH 0C-CH2CHNC0CH(CH3)2 .032 175 22.4 .079 1.46 86.6 34.5

4 Control .078 11.6 20.5 .072 1.03 87.4 45.1 5-- SameasRunNo.2 .078 14.3 18.4 .076 1.38 86.8 31.8 6 ..San1easRunNo.3 .078 11.2 17.8 .076 1.28 86.8 38.5

noaH.-0-ccmf -o-ocH oH3 was successfully employed as a flotation collector in the separation of copper sulfide from an ore.

One species of a flotation collector compound within the scope of the present invention, corresponding to the formula 0 S OH;

H H3CCH2OCCHT NHC 0 CH was prepared in the following manner:

An aqueous solution containing 21 grams of glycine ethyl ester hydrochloride was neutralized with an aqueous solution containing 6 grams of NaOH. The so-prepared solution of the employed and a product corresponding to the formula was obtained in about an percent yield.

Another species of a flotation collection compound within the scope of the present invention, corresponding to the formula was prepared in the following manner.

In a flask was placed 13.1 grams (0.l mole) of CH3CHCHC O O C2Hs and 13.6 grams (0.1 mole) of C H5-O- The mixture was heated to 55 C. and maintained at 5560 C. until CH SH was no longer observed to be evolved. The last of the CH SH was removed by heating to 55--60 under a reduced pressure of about 30 mm Hg. There was a 95 percent yield of an oily product.

The structure of the compound was confirmed by infrared and NMR analysis. Calculated analysis for the compound is C 49.29 percent, H-7.82 percent and No.39 percent. Actual partial analysis was 649.39 percent. H-7.72 percent and N- 6.38 percent.

In a manner similar to that employed in preparing the previous three compounds the amino ester was reacted with a technical grade xanthate ester corresponding to the formula cg, H s

cH-cm-o-o-c-som CH3 CH2 to give a product corresponding to the formula All of these compounds possess collector activity in the flotation separation of sulfide containing ores.

Other glycine esters corresponding to the general formula NH CH COOR, wherein R is the same as defined hereinbefore, can be employed in the processes previously defined to prepare flotation collector compounds for use within the scope of the present invention. For example R can represent, ethyl, chloroethyl, propyl, isopropyl, butyl, isobutyl, n-amyl, isoamyl, hexyl, octyl, dodecyl and other like groups.

The esters of such amino acids are made by standard procedures for the esterification of carboxylic acids, such as by heating the hydrochloride of the amino acid with alcohol in the presence of a catalytic amount of free HCl and then neutralizing to spring the free amino acid ester. Amino acids which can be used as their esters include for example, 2, or 4- aminobutanoic acids, 6-amino caproic, 2-amino-2-methyl propanoic acid, a and [3 alanine and other like amino acids. Amino acid esters of the following exemplary alcohols can be employed: 3-hexanol, 2, 3, S-trimethyl; 2-hexanol, 2, 3, 4, trimethyl; ethylene cyanohydrin; benzyl alcohol, cyclohexanol, cyclohexenol, cyclohexylmethyl alcohol, 4-chlorobutanol, 3-chloro-2-methyl-butyl alcohol, crotyl alcohol, 4- chlorocrotyl alcohol and other such alcohols.

Similarly, the -OR moiety in collector compounds hereinbefore defined as suitable for the practice of the instant invention can be derived from such of the above alcohols as do not comprise reactive halogen substituents.

Various modifications may be made in the present invention without departing from the spirit or scope thereof for it is understood that we are limited only as defined in the appended claims.

We claim:

1. In the process of concentrating sulfide ores by froth flotation in the presence of a flotation collector the improvement which comprises:

a. subjecting the sulfide ore in the form of a pulp to a flotation collector comprising a compound corresponding to the formula wherein R corresponds to a hydrocarbyl group selected from the group consisting of a alkyl or alkenyl group containing from 1 to 10 carbon atoms, a cycloalkyl, cycloalkenyl or an aralkyl group; R corresponds to an alkylene group, containing from 1 to 6 carbon atoms, and R corresponds to a hydrocarbyl group selected from the group consisting of an alkyl, cycloalkyl, cycloakenyl or alkenyl group containing from i to 8 carbon atoms, or an aralkyl or aralkenyl group.

2. The process as defined in claim 1 wherein from about 0.01 to about 0.25 pounds of said compound per ton of said sulfide ore pulp is employed.

3. The process as defined in claim 1 wherein said compound consists of 4. The process as defined in claim 1 wherein said compound consists of 5. The process as defined in claim 1 wherein said compound consists of 6. The process as defined in claim 1 wherein said compound consists of $1) CH H S OH: 

2. The process as defined in claim 1 wherein from about 0.01 to about 0.25 pounds of said compound per ton of said sulfide ore pulp is employed.
 3. The process as defined in claim 1 wherein said compound consists of
 4. The process as defined in claim 1 wherein said compound consists of
 5. The process as defined in claim 1 wherein said compound consists of
 6. The process as defined in claim 1 wherein said compound consists of 